U.S. patent application Ser. No. 404,791, now U.S. Pat. No. 4,569,674 issued Feb. 11, 1986, assigned to the assignee of the present invention, discloses a wound vacuum drainage system of the above mentioned kind.
While the latter has been found satisfactory in operation, Applicants have been engaged in a continuing effort to improve on systems of this type. Applicants have determined that by installing a hydrophobic filter in the drain reservoir, between the liquid chamber thereof and the vacuum passage, the apparatus of the prior application can be simplified, for example by elimination of a float valve, while protecting the vacuum passage in the drain reservoir and the vacuum pump in the base unit against contamination by wound drainage liquid from the drain reservoir.
However, Applicants have also found that wound drainage liquid often includes lipids (fatty substances) which tend to coat and hence clog the hydrophobic filter and that this may interfere with evacuating the drain reservoir to the desired subatmospheric pressure level, to enable continued vacuum draining of the wound.
Accordingly, the objects and purposes of this invention include provision of:
Apparatus for suction draining of a wound in which a hydrophobic filter is interposed in the connection between the reservoir chamber and the vacuum line to which the suction pump of a base unit are connectable, for preventing contamination of such vacuum passage and suction pump with wound drainage liquid.
An apparatus as aforesaid in which coating and hence clogging of the hydrophobic filter by lipids in the wound drainage liquid is prevented or avoided to increase the useful life span of the drain reservoir by making it possible to repeatedly charge same with vacuum by connection to a base unit.
An apparatus as aforesaid in which protection of the hydrophobic filter is provided at relatively low cost in a relatively simple manner.